Bugfix in predict.mppm and improvements to Metropolis-Hastings
algorithm.

   mhloop.c
     Pre-processing step now finds good initial state for any model
     by thinning initial state.

   methas.c
   mhloop.h
     New argument 'thin' determines whether initial thinning occurs.

   rmh.default.R
     Argument 'thin' issued in call to xmethas

   predictmppm.R
     Bug fixes thanks to Ege (problem raised by Markus Herrmann).

   NEWS
   DESCRIPTION
   spatstat-package.Rd
    Acknowledged Markus Herrmann.

   NEWS
   DESCRIPTION
    updated.
    Temporary version number: 1.39-1.028